1. Field of the Invention
The present invention relates to an imaging detecting element using a scintillator, which is caused to emit light by radiation.
2. Description of the Related Art
In a flat panel detector (FPD) to be used for X-ray imaging in clinical practice and the like, X-rays that has passed through a subject is received by a scintillator, and light emitted by the scintillator is detected by a photodetector. As a scintillator crystal portion, cesium iodide needle crystals formed by vapor deposition are used due to their ability of efficiently transmit emitted light to the photodetector. The needle crystals stand perpendicularly to the photodetector, and thus, a gap of air is naturally formed between the needle crystals. It is considered that, owing to the ratio between the refractive index of cesium iodide (about 1.8) and the air (1.0), light is totally reflected within the cesium iodide needle crystals having the higher refractive index to be effectively guided to the photodetector.